1. Field
Embodiments of the invention relate to electronic systems, and more particularly, to protection circuits for integrated electronic systems.
2. Description of the Related Technology
Certain electronic systems can be exposed to a transient electrical event, or an electrical signal of a relatively short duration having rapidly changing voltage and high power. Transient electrical events can include, for example, electro static discharge (ESD) events arising from the abrupt release of charge from an object or person to an electronic system. Transient electrical events can also include, for example, voltage spikes resulting from delivering a varying current to an inductive load, signals received by way of electromagnetic inductive coupling, or transient electrical events arising from starting a motor, such as a load dump transient electrical event resulting from starting an automotive engine.
Transient electrical events can destroy an integrated circuit (IC) inside an electronic system due to overvoltage conditions and high levels of power dissipation over relatively small areas of the IC. High power dissipation can increase IC temperature, and can lead to numerous problems, such as gate oxide punch-through, junction damage, metal damage, and surface charge accumulation. Moreover, transient electrical events can induce latch-up (in other words, inadvertent creation of a low-impedance path), thereby disrupting the functioning of the IC and potentially causing permanent damage to the IC from self-heating in the latch-up current path.
Certain integrated circuits, for instance, those used in automotive signal conditioning and sensing applications, are required to tolerate a relatively high level of over-voltage stress as well as false conditions at the input and/or output pins, such as short-to-battery condition. Thus, there is a need to provide an IC with protection from such transient electrical events. Furthermore, there is a need for a protection component providing an asymmetrical current versus voltage characteristics and that is able to safely sustain over-voltage stress and false conditions encountered in the relatively harsh automotive environment applications.